Scheduling and control of batch chemical processes with timed Petri nets
Wanzhen Lin, Ji Liang Luo, Jia Zhong Zhou, Yi Sheng Huang, Meng Chu Zhou · 2016
A formal approach is proposed for optimal scheduling and control problems in a batch chemical system. First, a method is presented to model it as a P-timed Petri net (PN), which can graphically describe how it may operate according to recipes, and which valve and pipeline are required by each operation. Second, this P-timed PN model is simplified according to the conflicts caused by the shared valves, and, in turn, it is utilized to define a linear programming where the optimal objective is the minimal processing time. Further, the A* algorithm is used to solve this programming to obtain an optimal strategy. Finally, via the P-timed PN model, a method is obtained to compute a control matrix for valves that can guarantee the optimal strategy. A typical batch system is used to illustrate the theoretic results.